viticella, C. flammula,
and C. vitalba move spontaneously; and, judging from C Sieboldi, this
probably is the case with C. montana and C. calycina. I ascertained
that the simple leaves of C. glandulosa exhibited no spontaneous
revolving movement.
Clematis viticella, var. venosa.--In this and the two following
species the power of spirally twining is completely lost, and this
seems due to the lessened flexibility of the internodes and to the
interference caused by the large size of the leaves. But the
revolving movement, though restricted, is not lost. In our present
species a young internode, placed in front of a window, made three
narrow ellipses, transversely to the direction of the light, at an
average rate of 2 hrs. 40 m. When placed so that the movements were
to and from the light, the rate was greatly accelerated in one half
of the course, and retarded in the other, as with twining plants.
The ellipses were small; the longer diameter, described by the apex
of a shoot bearing a pair of not expanded leaves, was only 4.625
inches, and that by the apex of the penultimate internode only 1.125
inch. At the most favourable period of growth each leaf would hardly
be carried to and fro by the movement of the internodes more than two
or three inches, but, as above stated, it is probable that the leaves
themselves move spontaneously.
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